Geezabloke Posted August 16, 2004 Share Posted August 16, 2004 I usually need the DSBC 3 set around 60 - 70% to get to 1.2 - 1.3bar. Allowing for changes in weather etc....i have noticed the boost raising to 1.3 - 1.4 this week even though the weather is hotter? Changed the settings down to 43% and still getting around 1.2 bar? Will set to 0% today then try with it OFF and see what happens? As im reaching boost it would suggest the pipes are ok? Could it be an actualtor sticking or solenoid gone wonky? Any advice appreciated Dave :flame Dev Link to comment Share on other sites More sharing options...
dude Posted August 16, 2004 Share Posted August 16, 2004 Its trying to tell you to go single !!!! Dude:flame Dev Link to comment Share on other sites More sharing options...
Alex Posted August 16, 2004 Share Posted August 16, 2004 Dude, dives in with another solution which costs thousands! lol It could be a small tear in a pipe causing a boost leak. you've said what it's SET to but what about the GAIN (or does the DSBC not have a GAIN setting?? I forget) Link to comment Share on other sites More sharing options...
SirCharlesworth Posted August 16, 2004 Share Posted August 16, 2004 Yeah it does have a gain setting- i think maybe it's down to air pressure rather than just heat this week though, because my car has dsbc and has been hitting the limiter tons this week when normally it wouldnt. Link to comment Share on other sites More sharing options...
Geezabloke Posted August 16, 2004 Author Share Posted August 16, 2004 UPDATE Cheers for your comments.......even Johns....how did i know that one was coming Have tried testing with Boost controller OFF....still hit 1.4 bar Have checked around acctuators for splits/loose hoses, all looks OK? Any simple tests to check acctuators etc...as it appears something may be stuck open/closed? Dave :flame Dev Link to comment Share on other sites More sharing options...
Steve W2 Posted August 16, 2004 Share Posted August 16, 2004 Originally posted by SirCharlesworth Yeah it does have a gain setting- i think maybe it's down to air pressure rather than just heat this week though, because my car has dsbc and has been hitting the limiter tons this week when normally it wouldnt. Why would air pressure effect the pressure in the turbo housing? Surely the reaction in the combustion chambers along with the movement of the wastegate are the only things that effect the turbo pressure. Or do you mean a higher back pressure (from the ambient air) against the the wastegate? In which case I would be surpirised if a few mbar would make a difference against 1.4 bar. Sticky wastgate actuator could be the problem. Certainly sounds like the pressure isn't being released somehow. Link to comment Share on other sites More sharing options...
Geezabloke Posted August 16, 2004 Author Share Posted August 16, 2004 Originally posted by Steve W2 Sticky wastgate actuator could be the problem. Certainly sounds like the pressure isn't being released somehow. Steve...that sound plausable.....what is the best/easiest way to test this? BTW found a hose off the rear actuator at back top of block, thought i had sussed it but made no difference.... Dave :flame Dev Link to comment Share on other sites More sharing options...
Steve W2 Posted August 17, 2004 Share Posted August 17, 2004 I don't know how easy this is to do but is it possible to put a supply onto the actuator terminals to 'manually' actuate it and listen to see if its getting stuck or if it moves from open to closed as it should. What is the control voltage for the actuator 4-20mA? Any technical bods? Link to comment Share on other sites More sharing options...
Geezabloke Posted August 17, 2004 Author Share Posted August 17, 2004 OK guys..have now checked all hoses, connections and VSV's all opening and closing ok. Did find one above the alternator with one side blocked off, but guess this is where the boost controller feed is fitted in line? So where do i check next? is there a simple test to carry out on the actuators? Could the fault lie with the SBC being stuck open or closed even though set to off? Am now lost as to what to check next? Dave :flame Dev Link to comment Share on other sites More sharing options...
Ian C Posted August 19, 2004 Share Posted August 19, 2004 Why would air pressure effect the pressure in the turbo housing? Surely the reaction in the combustion chambers along with the movement of the wastegate are the only things that effect the turbo pressure. Turbocharged cars are affected by atmospheric conditions that change the density of air. A cool damp day gives a denser intake charge. More air coming in means more exhaust going out (and more power ) so the turbo gets a bit more spin on it and sucks in a bit more air and so the boost pressure goes up. If you have a wastegate that can't quite cope with the exhaust flow of the turbo system then you'll see your boost pressure change as external air density changes. I don't know how easy this is to do but is it possible to put a supply onto the actuator terminals to 'manually' actuate it and listen to see if its getting stuck or if it moves from open to closed as it should. The actuators are mechanical devices, powered by boost pressure taken off the intake manifold, you are getting confused with the VSV that opens and shuts, controlling the flow of boost pressure to these actuators. Geeza - there is a way to test if the actuators are opening, although it doesn't test if they are *fully* opening. Get some tinfoil, fold it up so it's long and thin like a coffee stirrer stick. Wedge one end of it between an actuator and it's stop screw. Drive car - if tinfoil is still there after you've driven the car, then your actuator didn't open It's worked for me, diagnosed a non-opening EGCV actuator. Another test for your actual overboosting problem would be to wire the wastegate wide open. Boost will build slower but if it's a non-opening wastegate causing the problem, wedging it open will show this as your boost will return to normal levels. -Ian Link to comment Share on other sites More sharing options...
Geezabloke Posted August 20, 2004 Author Share Posted August 20, 2004 Update Well guys.......it turns out that when the boost controller was fitted one of the hoses bypassed was cut and had a screw inserted to blank it off.......you guessed it..said screw had come out and hey presto..too much boost..... Thanks to one and all for comments and advice and to the Dude with the loud shirt collection for confirming the prob and putting right............ Dave :flame Dev Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 20, 2004 Share Posted August 20, 2004 don't forget the telephone help line................... Link to comment Share on other sites More sharing options...
Geezabloke Posted August 20, 2004 Author Share Posted August 20, 2004 Originally posted by Terry S don't forget the telephone help line................... The telephone helpline wasnt operating at all times.......something to do with single members only?..lol Link to comment Share on other sites More sharing options...
dude Posted August 20, 2004 Share Posted August 20, 2004 Dave was so impressed with my single all his hair fell out Dude:flame Dev Link to comment Share on other sites More sharing options...
Geezabloke Posted August 21, 2004 Author Share Posted August 21, 2004 Originally posted by dude Dave was so impressed with my single all his hair fell out Dude:flame Dev John you have to admit that since driving mine youve now seen the light....lol Or many of them... Dave :flame Dev Link to comment Share on other sites More sharing options...
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